Electro-Voice 250, 1252 operation manual Power Source for I/O Modules

9.2.1: Power Source for I/O Modules

The Nexus 1250/1252 will supply power to a limited number (3) I/O MODULES. For more, you must use an external power source, such as the EIG PSIO (12V). Refer to sections 5.12 and 5.13 to Determine Power Needed. RS-485 communication is viable for up to 4000 feet (1219 meters).

You must also do the following:

1.Connect the A(+) and B(-) terminals on the Nexus to the A(+) and B(-) terminals of the male RS-485 port. Connect the shield to the shield (S) terminal. The (S) terminal on the Nexus is used to reference the Nexus port to the same potential as the source. It is not an earth ground connection. You must also connect the shield to earth-ground at one point.

2.Put termination resistors at each end, connected to the A(+) and B(-) lines. RT is ~120 Ohms. NOTE: Refer to section 5.3 for RT Explanation.

3.Connect a source of power to the front of the module.

SIDE LABEL

.08” 4

3
.
	42”

1.72”

TOP LABEL

Figure 9.3: The PSIO Power Source (Side View)

showing Male RS-485 Side Port

Figure 9.4: Power flow from PSIO to I/O Module	Figure 9.5: Labels for the
	PSIO Power Source
	(Labels are Red & White.)

Electro Industries/GaugeTech Doc # E107706 V1.25 9-4